JPS62192540A - Floatation supporting apparatus for converting sheet passing direction of running strip body - Google Patents

Abstract

PURPOSE:To convert a direction of strip body with a fixed locus and stabilize passing of sheet, by applying pressing means due to gas jetting to a pressure receiving surface of a bender floater, at a space from starting end at inlet side of strip body loop to the terminal end at exit side. CONSTITUTION:In floatation supporting apparatus for running strip body, small sized floaters F' are opposedly provided at both ends and middle part of the pressure receiving arc surface G of the bender floater F, and a strip 1 is passed between both. The strip 1 receives pressing force due to static gaseous pressure from the floaters F'. If the strip 1 wishes to move the sheet passing locus to the outside, static pressure between a pressure receiving surface G' of the floater F' and the strip 1 is raised and it is pushed back to the former passage by the increased static force. Together with this, action for suppressing vibrations such as lateral shaking, twisting and waving and straightening deformation such as warping of the strip 1 are applied at inlet side of loop. Sheet passing direction can stably be converted by the apparatus.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to annealing furnaces for various metal strips, heat treatment equipment, plating lines, coating lines, and non-contact threading in various processing lines for non-metallic strips. Relating to a direction change device.

[Conventional technology]

As an example of a conventional technique, a continuous strip annealing furnace for cold-rolled steel sheets will be outlined based on FIG. 4.

In the figure, an IJ tube 1 made of a cold-rolled steel plate is supplied to a continuous annealing furnace through a looper, a cleaning tank, a dryer, etc. (not shown). The strip 1 is passed through an annealing furnace filled with reducing gas to prevent surface oxidation, for a distance of approximately 20 meters between two schools 2 arranged above and below the furnace.
I&: It travels at a speed of 200 to 500 m/wrrtt while changing direction up and down, and undergoes a predetermined heat treatment. Looking at this in terms of equipment, the strip 1 is first heated in the heating zone A by the radiant tube 3 to a temperature of about 650 to 900°C, although it varies depending on the type of n4. After that, it is soaked for several tens of seconds in soaking zone B, and then cooled to 350 to 400 degrees Celsius at a cooling rate of 3 to 200 degrees Celsius per second by gas jet in rapid cooling zone C.
It is rapidly cooled to about ℃. Next, this cooling temperature (350~4
00° C.), undergoes an overaging treatment for about 2 minutes, and is finally cooled down to room temperature in a rapid cooling zone E.

By the way, this hearth roll 2 has a diameter of 800 to 10
00rtrm, thickness 10~20ym, length 2000~2
It is made of cast steel and has a cylindrical shell of 500 ra. Each one is directly connected to an electric motor whose rotation speed is controlled by voltage and frequency, and the drive is changed. Usually, 50 to 100 hearth rolls are used in one annealing furnace. used in

[Problem that the invention seeks to solve]

As mentioned above, in annealing furnaces equipped with many large rolls, this has not yet become a major problem, but
As the strip speed increases to 1,000 to 2,000 m/HIlt, it is necessary to synchronize the traveling speed of the board with the circumferential speed of the hearth roll with very strict precision, but because the inertia of the roll and the inertia of the motor are large. It is nearly impossible to match exactly.

As a result, the slippage between the strip and the hearth roll becomes larger than when the speed is low, causing scratches on the strip surface and changing the length of the strip between the upper and lower hearth rolls, causing vibration. or In addition, in continuous annealing furnaces, push kisses on the strip (referred to as roll pickup) occur due to rough skin of the roll, which is thought to have its origin in the seizure phenomenon between the roll and the strip at high temperatures of 80°C or higher. There is a problem, and this countermeasure is also needed.

Furthermore, when a cold strip comes into contact with the center of a roll heated by a radiant tube, tracking defects may occur due to a 7'0 film change in the length direction of the roll (referred to as heat crown) due to thermal contraction of the center of the roll. There's a problem.

In order to solve the problems with the conventional direction changing device using hearth rolls as described above, a system as shown in FIG.
The present inventors have proposed a floating support device (hereinafter referred to as a bender) that changes the running direction while floating the strip using gas pressure. However, this bender floater has the following problems.As the speed of the double plate increases, when the strip is suspended by the bender floater and changes direction, centrifugal force acts on the strip, causing As shown by the solid line in Figure 5, near the exit side of the bender floater F, the band loop L bulges outward from the normal position shown by the dashed line and moves away from the support surface G of the bender floater F. Therefore, due to the decrease in the buoyancy force (static pressure) of the bender floater F due to the leakage of the gas pressure to be maintained between the floater and the strip (strip 1), 70
There is a risk of contact with the strip near the top of the 70-meter, and to prevent this, it will be necessary to supply a larger amount of gas to the 70-meter, but such measures will reduce gas consumption. Not only does this increase the temperature, but it also causes the strip-shaped body facing the inlet and outlet sides of the floater to be further separated outwards, which becomes a factor that makes the running of the strip-shaped body unstable. The general structure of the bender floater b is as follows: 4 divided cylindrical hollow gas chambers
Then, the gas supply pipe 5 that supplies air, inert gas, or reducing gas into the gas chamber 4 is opened, and the arcuate outer peripheral surface of the hollow gas chamber 4 acts as a pressure receiving surface G. Nozzles 6 are opened inward at both ends of the pressure-receiving surface G, and the gas in the gas chamber 4 is ejected to confine the gas between the strip 1 to be supported and the pressure-receiving surface G and generate static pressure. , which supports the strip 1 in a floating manner.

Note that H denotes a plurality of ribs planted on the pressure receiving surface G along the threading direction of the strip 1 to reduce leakage of the gas in the width direction of the IJ tube. Also, F'
is the aforementioned vendor floater? This floater is basically the same as the bender floater F except that its pressure receiving surface G' is flat.

[Means for solving problems]

A bender floater in which an arc-shaped loop is formed in the belt-shaped body at a portion where the running belt-shaped body changes the threading direction, and the belt-shaped body loop is suspended and supported on an arc-shaped pressure-receiving surface by gas pressure caused by gas jetting on the inner circumference side. will be established. Furthermore, all of the section from the entrance end of the strip loop to the loop exit end,
Alternatively, a band-shaped body pressing means by jetting gas is provided opposite to the pressure-receiving surface of the bender floater so as to cover at least a portion of the starting end and the terminal end.

[Effect]

With the above configuration, when the strip is suspended on the bender floater and the threading direction is changed, the gas pressure by the strip suppressing means moves the strip loop to the position where it balances the pushing force by the penguro 70-tor. It is pushed back to the receiving surface side, and while the strip maintains a predetermined loop shape, it can change the threading direction with a constant trajectory.

Therefore, the bender floater and the strip can maintain a certain preferable gap, so there is no waste of gas supplied to the floater, and the buoyancy force acts effectively on the strip, and the flow of the strip The board will be stabilized.

〔Example〕

Hereinafter, the present invention will be explained based on embodiments and with reference to the drawings.

Figures 1 and 2 show a continuous annealing furnace for cold-rolled thin steel sheets (0.4 to 2.oMa thickness), in which a bender floater is used instead of the conventional hearth roll as the traveling steel strip.

1 is a schematic diagram of a floating support device for changing the direction of sheet passing, FIG. 1 is a side sectional view of the device, and FIG. 2 is a front view of the device.

In the figure, F is a bender floater which constitutes the main body of the device, and its structure is the same as that explained with reference to FIG. This floater? are arranged in an overlapping manner in the annealing furnace, vertically in the case of a vertical pass, and left and right in the case of a horizontal pass, and the IJ tube 1 is suspended by these floaters F to change the sheet threading direction to '1iso'. The plate is threaded from the furnace inlet to the outlet.

4 is a hollow gas chamber of the floater F, 5 is a gas supply pipe for supplying pressurized gas into the hollow gas chamber 4, 6 is a slit-shaped nozzle that opens inwardly at both ends of the floater, and G is a bender floater. On one side of the wall of the hollow gas chamber 4, F is a semi-cylindrical pressure receiving surface, and H is a lip planted parallel to the pressure receiving surface at intervals in the direction of the door. L is an arcuate loop of the strip 1 formed when the strip 1 is suspended on the inner floater F' and completely changes the direction of sheet passing.

F' is a small floater installed as means for suppressing a band-shaped object by ejecting gas, and its structure is basically the same as that of the bender floater F described above.

In the pressure receiving surface of the bender floater F, that is, in the section from the starting end of the arc of the loop L to the exit end of the arc, one floater F' is provided at the starting end, and further spaced at appropriate intervals on the terminal end side. Two of them are placed directly opposite the pressure receiving gG. However, the number of installations is not limited to the above.

Now, in such a configuration, the vendor floater F
During relatively low-speed threading, the suspended strip 1 forms a loop almost following the curvature of the pressure-receiving surface G of the floater, and the gas ejected from the floater nozzle 6 forms a loop between the strip 1 and the pressure-receiving surface. It is buoyed and supported by the static pressure generated by the containment, and the direction is changed and the plate is passed through. However, as the threading speed increases, centrifugal force acts on the strip 1 due to the curvature of the pressure receiving surface G due to the pengulet 70-ta F.
As shown in FIG. 5, the strip 1 resists the tension applied to it and tends to move outward from the pressure-receiving surface G, and this tendency increases as the threading speed increases. If the strip is too far away from the pressure-receiving surface, the static pressure between the pressure-receiving surface of the inder floater F and the strip will naturally decrease, reducing the buoyancy force, and the strip during threading will come into contact, especially at the top of the inder floater 70-ta. As mentioned above, not only is there a risk of the strip passing, but also the strip threading becomes unstable.

In addition, if the strip entering the floater entry side has vibrations such as lateral wobbling, twisting, or waving, or deformations such as C or L, and is suspended on the floater li'' without being corrected. , the buoyancy force acting in the width direction of the strip becomes uneven, and the threading direction becomes even more unstable.

Therefore, in the present invention, as shown in FIG.
They were placed opposite to each other at both ends and at the middle of G, and a strip 1t was passed between them.

Incidentally, in a device intended for relatively low-speed sheet passing, the floater in the intermediate portion may be omitted. In this way, the strip 1 that passes between both floaters I', F'/ is subjected to a pressing force due to the static gas pressure from both floaters, but this force is equal to the distance from the pressure receiving surfaces G, G' of both floaters to the strip 1. If the strip 1 is subjected to centrifugal force and tries to move outward along its threading trajectory, that is, when it approaches the pressure receiving surface G' of the floater F', the pressure receiving surface G' , and the strip 1, and this increased static pressure acts to push the IJ tube 1 back into its original path, and at the same time prevents the strip from swaying or twisting on the loop entry side. Calms vibrations such as medium waves,
It also acts to correct deformities such as C-zoshi and L-zoshi.

Thus, the IJ tube 1 can stably pass through the IJ tube 1 with a substantially constant trajectory while maintaining the normal loop L.

In the other embodiment shown in FIG. 3, the floater F" adopted as means for pressing the strip by ejecting gas has a dimension that covers the entire section from the start end of the loop L to the end end of the loop exit side, as shown in the figure. , and its pressure-receiving surface G
The curvature of " is concentric with the pressure receiving surface G of the bender floater F.

According to this method, the direction change of the strip 1 is further facilitated, and the strip 1 is stably threaded while drawing a nearly constant threading trajectory. It is particularly suitable for strip-shaped plate materials and thin strip materials with low rigidity. In addition, as a means for pressing the band-shaped object by blowing out gas,
In addition to the static pressure method used in this embodiment, a dynamic pressure method using a high-speed gas jet can also be used.

Furthermore, although the bender floater F shown in Figs. 1.2 and 3 is formed as an integral floater with a substantially semi-cylindrical pressure receiving surface G, it may be divided into a plurality of parts or The pressure receiving surface may be provided with a plurality of pairs of nozzles, or the hollow gas chamber 4 may be divided into a plurality of sections.
Further, the curvature of the pressure receiving surface G does not necessarily have to be a circular arc.

〔Effect of the invention〕

According to the present invention, this problem occurs when the strip is separated from the pressure receiving surface of the floater due to the centrifugal force that acts during high-speed sheet passing, which occurs in the conventional floating support device in which the sheet is buoyed and supported by a bender floater and the sheet passing direction is completely changed. Decreased buoyancy force of the floater, occurrence of flaws due to contact between the floater and the strip, vibration and deformation of the strip, instability of plate threading, or waste of gas supplied to the 70-meter. Problems such as these can be effectively prevented and a stable sheet passing direction changing device can be realized.

[Brief explanation of drawings]

1 and 2 schematically show a floating support device for changing the direction of sheet passing according to an embodiment of the present invention, FIG. 1 is a side sectional view of the device, and FIG. 2 is a front view of the device. FIG. 3 is a side sectional view of the apparatus according to another embodiment of the present invention, FIG. 4 is a schematic diagram of a continuous strip annealing furnace for cold-rolled steel sheets using a conventional hearth roll, and FIG. FIG. 6 is a diagram showing the state of deflection of the suspension strip loop that occurs during high-speed sheet passing. 1...Strip 4...Hollow gas chamber 5...
Gas supply pipe 6...Nozzle F...Bender floater F', F/(...Floater G, G', G"...
Pressure-receiving surface H...Rep L...Lunip sub-agent Patent attorney Shigefumi Okamoto and 2 others Figure 2

Claims (1)

[Claims] When changing the passing direction of the traveling strip, an arc-shaped loop is formed in the strip, and a bender floater is installed on the inner circumferential side of the loop to float and support the strip loop on an arc-shaped pressure-receiving surface using gas pressure caused by gas jetting. In the floating support device for changing the direction of sheet passing, the belt-shaped body press means by blowing out gas so as to cover the entire section from the entrance side starting end to the exit side terminal end of the belt-shaped body loop, or at least the starting end and the terminal end portion. A floating support device for changing the direction of sheet passing of a running strip, characterized in that: is provided opposite to the pressure receiving surface of the bender floater.